A magnetic core comprises an anisotropic, composite material, which itself includes a matrix material (e.g., a dielectric, non-magnetic material, preferably a paramagnetic material), and magnetically aligned, ferromagnetic particles. The latter may for instance include micrometer- and/or nanometer-length scale particles. Such particles form chains of particles within the matrix material, wherein the chains form percolation paths of magnetic conduction. The paths extend along a first direction, whereby the chains extend, each, substantially along this first direction, while being distinct and distant from each other along a second direction that is perpendicular to the first direction and, possibly, to a third direction that is perpendicular to both the first direction and the second direction. Necking bridges are preferably formed between the particles. Related devices (e.g., inductor, amplifiers, transformers, etc.) and fabrication methods are also disclosed.